Marantz 2245 User manual

"SERVICE.

_MANUAL

|

model

2245

|

Bgi

TABLE

OF

CONTENTS

CG

SECTION

7

:

PAGE

Introduction........

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Tenner

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acd

Swe

Wk

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Sg

er

a

ee

Bo

eevee

Galaens

wae

ae

ine

er

ays

2

Phono

and

Tone

pan

HStS

ae

imate

haa

Ysee

Baw

Sulstes

eaieice

nage

ane

ecae

tees

ee

ais

or

gest

4

Power

Amplifier

iscc

io.

s

cc's

6

dete

o's

SS

ae

SW

in

CR

CES

ne

Oe

RR

Re

Oa

Ee

SG

5

Power

Protection

Circuit

..

6...

0

cee

ee

eect

eee

ee

eee

eens

2a

5

Speaker

Protector

Relay

Circuit

..

0.2.0.6.

cece

eee

tee

mee

5

Suggestions

for

Trouble

Shooting

of

Power

Amplifier

Jahre

wie

hee

Beet

ae

Wage

le

De

GR

eds

6

Voltage

Conversion...

.....0

0c

cece

c

cece

cc

tenet

eee

e

eee

eseeenee

mae

6

Test

Equipment

Required

for

Servicing

...........-

0c

eee

3,

23

ns

B

AM

Alignment

Procedure

.......

0.60

c

eee

ee

cece

eee

ence

nseeenstesessscens

er

ate

(A

FM

Alignment

Procedure

.......-..

ccc

cece

c

cece

erence

ttre

et

ee

tet

teene

me

.

&9

STEREO

Separation

Alignment

........

06.

ce

cece

eee

ee

tee

eee

-..

9

Muting

Circuit

Alignment..............-22-06%

signed

fe

Anh

a

bit

Gate

Gio

we

ere

eeate

ae

@

eta

10

Audio

Adjustment:

sc65

eshte)

ae

ih

etek

ee

eee

ROR

ee

eee

sa se

ee

aye

ssa,

oe

10

Parts:

List.

03

deuce

ete

seas

a8

Bae

gt

geaaee

ie

Cena

tats

(icG,

BGR

elses

Mate

ae

ar

ah

aso

say

ice

«ane

21

Specifications

........

0.02

cc

eee

cence

creer

cee

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ah

ee

Se

eae

-..29

LIST

OF

ILLUSTRATIONS

FIGURE

:

.

PAGE

1.

Remove

the

Terminal

Cover

........0

20:

e

eee

cece

eee

e

een

nee

mae

6

2.

Voltage

Conversion

Chart

..........

Tae

eRe

ea

lee

Rea:

Smee

oie,

tents

_7

3.

Lissajou

Figure

on

Oscilloscope

....

1.2...

ce

eee

nets

Tide.

tees

od

4,

Dial

Stringing.

.....

6.

ecw

ce

cere

c

cece

eet

eee

eet

ee

tere

eeee

-..11

5.

Front

Panel

Adjustment

and

Component

Locations

...........00c

cece

eeee

ere

WZ

6.

Main

Chassis

Component

Locations

(Top

View)

...........0050ee

eee

deat

tas

o%

~..12

7.

Rear

Panel

Adjustment

and

Component

Locations

................eeeeeees

-

«+.

13

8.

Main

Chassis

Component

Locations

(Bottom

View)

.............00e

eee

Sas

SS

9.

FM

Front

End

Assembly

P100

Component

Locations........

da

ic

deat

Sra

abner

Ba

-..

14

10.

FM

IF

Amplifier

Assembly

P200

Component

Locations

......

Nisbet

aneehats

4,6

a

tas

11.

FM

Detector

Assembly

P500

Component

Locations

.............22200

ee

eee

oe

15

12.

MPX

Stereo

Decoding

Amplifier

Assembly

P300

Component

Locations........

Scala

e.

BS

13.

Muting

Control

Amplifier

Assembly

P550

Component

Locations

.............

-

-..

16

14.

AM

Tuner

Unit

Assembly

P150

Component

Locations

.............0000

0

eee

e

wee

16

15.

Phono

Amplifier

Assembly

P700

Component

Locations

.............06+.e20

2 2

ee

17

16.

Tone

Amplifier

Assembly

P400

Component

Locations

.................0055

e

225.17

17.

Power

Amplifier

Assembly

P750

Component

Locations

..........

Sa

aaieth

tna

Jada

-

-«..

18

18.

Regulated

Power

Supply

and

Protection

Relay

Circuit

Assembly

P800

Component

Locations

..........

0.

cece

eee

ee

eee

tee

mae

19

19.

Loudness,

High

and

Low

Filter

and

Muting

Switch

Unit

Assembly

P6OO

Component

Locations

........

2...

ccc

eee

cette

eee

we

19

20:

Schematic

Diagranit

io.

sao

ook

Ps

ek

Sas

Ce

ede

eee

he

ies

Geer

i

20

5.

Power

Amplifier

The

signal

from

the

tone

amnplitiek

is

applied

to

the

differential

amplifier

(base

of

H751)

through

the

coupling

capacitor

C751.

The

differential

amplifier

provides

very

high

input

impedance

and

its

collector

output

(H752)

is

applied

to

the

base

of

H753

which

in

turn

applies

its

Output

to

the

H756

through

the

network

R766,

C762

and

R771,

and

to

the

H757

through

the

network

R776,

C763

and

R772.

The

outputs

of

H756

and

H757

are

applied

to

the

H758

and

H757

respectively.

HOO1

and

HOO2

are

power

transistors

used

in

complementary

symmetry

configulation

and

mounted

on

the

heat

sink.

To

maintain

overall

amplifier

stability

and

linearity,

degenerative

feed

back

is

utilized

throughout

the

amplifier.

This

feed

back

is

also

necessary

to

reduce

distortion

to

within

specified

limit.

The

RC

network

R775

and

C756

condition

the

feed

back

signal

for

the

audio

signals.

R759

and

C755

are

also

a

feed

back

loop

provided

to

obtain

a

stable

zero

DC

off

set

voltage

at

the

speaker

output

terminals.

The

R762

is

a

trimming

resistor

to

adjust

the

DC

off

set

voltage.

Dynamic

bias

is

applied

to

the

base

of

driver

transistors

H758

and

H757.

This

dynamic

bias

circuit

is

comprised

of

H761,

H760

and

R763.

This

provides

a

variable

base

bias

for

driver

transistors

that

automatically

maintains

the

proper

base

voltage

with

temperature

change.

The

temperature

sensitive

biasing

components

of

the

dynamic

circuit

are

thermally

couppled

through

a

heatsink

to

the

power

amplifier

transistors.

6.

Power

Protection

Circuit

Protection

circuit

for

the

amplifier

is

provided

by

sensing

resistor

networks

and

two

switching

transistors.

When

the

output

transistors

are

over-driven,

the

current

increase

through

the

power

output

transistor

causes

an

increased

current

flow

through

R789

(or

R788)

and

the

potential

across

the

R789

wil!

be

increased.

This

increased

voltage

potential

is

applied

to

the

base

of

H755

through

the

resistor

R783

and

turns

on

the

H755.

Since

the

collector

of

H755

is

directly

connected

to

the

base

of

H757,

this

means

that

the

base

of

H757

is

bypassed

to

the

ground

through

emitter-collector

path

of

H755.

Thus

the

input

signal

to

the

H757

is

restricted

to'the

value

which

maintains

the

operation

of

power

transistor

with

in

the

safety

area.

A

resistor

network

R777

and

R781

also

works

as

a

sensing

network.

When

the

center

voltage

(collector

voltage

of

power

transistors)

is

excessively

increased

to

a

positive

value

by

certain

troubles,

the

voltage

applied

to

the

base

of

H755

makes

the

H755

turn

on,

making

bypass

circuit,

and

protects

the

power

transistor.

For

the

other

half

cycle

of

driving

signal,

the

pperaung

principle

is

applied

provided.

7.

Speaker

Protector

Relay

Circuit

The

speaker

protection

cureant

consisting

of

H808,

H809,

H810,

etc

protects

the

speaker

systems

against

any

loud

“pop”

sound

developed.

This

circuit

is

so

designed

that

no

sound

is

heard

for

the

first

three

or

five

seconds

after

the

power

switch

is

turned

on

by

the

time

constant

circuit

consisting

of

C807

and

R816.

This

circuit

also

protects

the

speaker

systems

against

some

troubles

due

to

DC

off

balance

between

the

speaker

system

terminals

by

instantly

operating

the

relay

and

cut

off

the

speaker

systems

from

the

circuit.

When

DC

off

balance

valtage

(positive)

is

developed

between

speaker

terminals

by

possible

defects

such

as

broken.

power

transistor,

short-circuits,

or

broken

potentio

meter

R762,

as

the

base

of

H808

is

connected

to

the

speaker

terminal,

the

transistor

H808

is

turned

on

by

this

offset

voltage

developed

and

this

makes

the

transistor

H809

and

H810

turns

off,

thus

cutting

off

the

relay

and

disconnecting

the

speaker

from

the

output

circuit.

When

negative

offset

voltage

is

developed,

this

voltage

directly

turns

off

the

H809

and

H810,

thus

speaker

is

cut

off

from

the

circuit

and

protected.

The

circuit

also

protects

the

speaker

systems

from

the

possible

damage

when

the

amplifier

is

over-driven

by

very

tow

frequencies

such

as

7

or

lower

cycles.

|

8.

Suggestions

for

Trouble

Shooting

of

Power

Amplifier

8.1

Excessive

Line

Consumption

a.

Check

for

shorted

rectifiers

HOO5;

also

check

C007

and

COO8.

b.

Check.

for

shorted

transistors

H758

and

H759,

HOO1

and

HO02,

or

check

H760.

Check

for

open

control

R763,

and

bias

diode

H761.

Check

L004

for

short.

CAUTION:

BECAUSE

THE

DRIVER

AND

OUTPUT

STAGES

ARE

DIRECT

COUPLED

COMPONENTS

MAY

FAIL

AS

A

DIRECT

RESULT

OF

AN

INITIAL

COM-

PONENT

FAILURE.

IF

A

SHORTED

TRANSISTOR

OR

ZENER

DIODE

IS

FOUND,

OR

CONTROL

OR

BIAS

DIODE,

BE

SURE

TO

CHECK

THE

REMAINING

DRIVER

AND

OUTPUT

COMPONENTS

FOR

SHORT

OR

OPEN

CIRCUIT

BEFORE

RE-ENERGIZING

THE

AMPLIFIER.

8.2

No

Line

Consuniption

or

Zero

Bias

a.

Check

line

cord,

fuse,

transistors

H760,

HOO1,

HOO2.

HOO3

and

H004,

bias

diode

H761.

b,

Check

for

open

rectifier

HOO5,

or

open

L004.

8.3

No

DC

Balance

a.

Check

R762

and

Zener

diodes

H762

and

H763.

9.

Voltage

Conversion

This

model

is

equipped

with

a

universal

power

transformer

to

permit

operation

at

100,

120,

200,

220

and

240V

AC

50

to

60Hz.

To

convert

the

Model

2245

to

the

required

voltage

perform

the

following

steps:

(1)

Remove

the

top

cover.

(2)

Remove

the

Transformer

Wire

Connection

Terminal

Cover,

loosen

two

Cover

mounting

screws

on

the

rear

panel,

see

Fig.

1.

(3)

Change

the

jumper

wires

as

illustrated

in

Fig.

2

for

the

required

AC

voltage

and

replace

the

'

fuse

as

instructed.

CAUTION:

DISCONNECT

POWER

SUPPLY

CORD

FROM

AC

OUTLET

BEFORE

CONVERT-

ING

VOLTAGE.

REMOVE

SCREW

REMOVE

THIS

COVER

Figure

1.

Remove

the

Terminal

Cover

For

100

V

Operation

For

200V

pea

(Use

4A

Fuse

)

(Use

3A

Fuse

BROWN

GREEN

WHITE

RED

BLUE

YELLOW

BROWN

GREEN

WHITE

RED

BLUE

YELLOW

—

For

120

V

Operation

For

220V

Operation

(Use

3A

Fuse

)

(Use

3A

Fuse

)

BROWN

GREEN

WHITE

RED

BLUE

YELLOW

BROWN

GREEN

WHITE

RED

BLUE

YELLOW

For

240V

Operation

(Use

3A

Fuse

)

BROWN

GREEN

WHITE

RED

BLUE

YELLOW

Figure

2.

Voltage

Conversion

Chart

10.

Test

Equipment

Required

for

Servicing

Table

1

lists

the

test

equipment

required

for

servicing

the

Model

2245

Receiver.

Manufacturer

and

Model

No.

AM

Signal

Generator

Test

Loop

FM

Signal

Generator

Stereo

Modulator

Audio

Oscillator

Oscilloscope

VTVM

Circuit

Tester

AC

Wattmeter

AC

Ammeter

Line

Voltmeter

Variable

Autotransformer

(0-140VAC,

10

amps.)

Shorting

Plug

Output

Load

(8

ohms,

0.5%,

100W)

Output

Load

(4

ohms,

0.5%,

100W)

Less

than

0.3%

distortion

Less

than

0.3%

distortion

Weston

Model!

CVO-100P,

less

than

0.02%

residual

distortion

is

required.

High

sensitivity

with

DC

hori-

zontal

and

vertical

amplifiers.

With

AC,

DC,

RF

range

Simpson,

Model

390

Commercial

Grade

(1-10A)

Commercial

Grade

(0-15VAC)

Powerstat,

Model

116B

Use

phono

plug

with

600

ohm

across

center

and

shell.

Commercial

Grade

Commmercial

Grade

Signal

source

for

AM

align-

ment

Used

with

AM

Signal

generator

Signal

source

for

FM

_align-

ment

Stereo

separation

alignment

and

Trouble

Shooting

Sinewave

and

squarewave

sig-

nal

source.

Waveform

analysis

and

trouble

shooting,

and

ASO

alignment.

Voltage

measurements

Trouble

Shooting

Monitors

primary

power

to

Amplifier.

Monitors

amplifier

output

un-

der

short

circuit

condition.

Monitors

potential

of

primary

power

to

amplifier.

Adjusts

level

of

primary

power

to

amplifier.

Shorts

amplifier

input

to

elimi-

nate

noise

pickup.

Provides

8-ohm

load

for

ampli-

fier

output

termination.

Provides

4-ohm

load

for

ampli-

fier

output

termination.

protection

relay

has

been

operated

or

not.

(When

the

relay

has

been

operated,

no

signal

is

provided

to

the

speaker

terminals.)

If

there

is

no

signal

at

the

speaker

terminals,

turn

off

the

system

power

of

the

amplifier

for

about

one

minutes,

then

again

turn

on

the

power

and

adjust

the

R782

and

R783

for

a

slight

increased

height

of

A

and

B.

6.7

For

the

another

Main

Amplifier,

repeat

the

procedures

6.2

to

6.6.

co)

10

20

30

40

50

60-70

80

Vce(V)

Figure

3.

Lissajou

Figure

on

Oscilloscope

8

XQ

NN

START

FINISH

SS

_

1

Nee

POINTER

Figure

4,

Dial

Stringing

11

12

Tuning

Knob

S60I-4

S0O05-I1

SO05-2

S003

JOO9

MOO!

MOI7

S004-2S6O0I-|

S60I-2

sS60I-3

=

teedble

halar\ce

volurn|

JOO8

SO04-I

-

SO02

R469

R470

R47I

ROOS

ROOG6

JOIO

Figure

5.

Front

Panel

Adjustment

and

Component

Locations

P800

PI0O

P500

PI50

P500

HAL

ee

er

BRR

EE

Ns

mePert

la:

HOO!

HOO2

TIGKIE

SY

ist

100]

£2

lta

a

Na

P750

C007

coos

Jolgs

LOO4

P550

L75i

P750

Figure

6.

Main

Chassis

Component

Locations

(Top

View)

JOO02

SPEAKE|?

SYSTEMS

JOO3

ZOOW

MEX

TOTAL}

1OOW

frax

TOTAL

JOIZ

Jol2

JOI!

P700

LOO!

soo!

JOO!

QUADRADIAI

°

3

oe

JO2O0

JOO6

JOO7

JOIS.

VyOOS

Figure

7,

Rear

Panel

Adjustment

and

Component

Locations

P450

P400

P2000

Cd

a

I

wil

a

cd

i’

aE

,

Ct

Figure

8.

Main

Chassis

Component

Locations

(Bottom

View)

|

HI

|

le

im)

Jons

FM

Front

End

Assembly

P100

Component

Locati

igure

9.

F

ier

Assembly

P200

Component

Locations

Figure

10.

FM

IF

Ampli

14

C306_H305,

®

:

for

[RS18

+S

10

H3l2

aN

Cc3it

SON

_R3748

2R333(e}—«

e

a

[e2]

Pa

.

ede

m

.

oO

332

=

i

+

fesez}

ae

I

|

=

ae

SS

VE)

taser

+

STE)

oe

C334

C333

J3I2

aes

Figure

12.

{iPX*Stereo

Decoding

Amplifier

Assembly

P300

Component

Locations

15

Figure

13.

Muting

Control

Amplifier

Assembly

P550

Component

Locations

Figure

14.

AM

Tuner

Unit

Assembly

P150

Component

Locations

16

H705

C707

H703

;

H70I

H706

c7os

9

§=H704

H702.

Figure

15.

Phono

Amplifier

Assembly

P700

Component

Locations

H404

H402

H401

H403

Figure

16.

Tone

Amplifier

Assembly

P400

Component

Locations

17

18

REF.

MARANTZ

DESIG.

PART

NO:

|.

DESCRIPTION

MECHANICAL

PARTS

A

281940140

|

Frame

Assembly

“REF.

MARANTZ

DESIG.

|

PART

NO.

DESCRIPTION

0330

281927106

|

Holder

0331

281827103

|

Holder

281906301

Escutcheon

281927107

|

Holder

281840101

Frame

281805101

Guide

281815801

|

Window

28186005

©

Bracket

i

273125901

Bush

281810650

|

Bearing

K

281905302

|

Coverx3

:

281825905

257811202

|

Shaft

(Fly

Wheel)

Bush

x

9

=

281826250

|

Pulley

K

>

281815440

|

Knob

Assembly

(Tone)

x

3

281926251

|

Pulley

K

281815404

|

Knob

257912001

|

Insulator

714001490

|

Spring

281812001

|

Insulator

141511801

|

Spacer

281815441

|

Knob

Assembly

(Double)

(Tone)

x

3-

257710602

|

Bearing

28185405

Knob

257816052

|

Bracket

K

714001590

|

Spring

145525901

|

Bushx

2

53228059E

|

Nut

(Muting

Vol.)

|

281816040

|

Bracket

Assembly

(Front)

{

281811801

|

Spacer

’

281816006

|

Bracket

|

281816001

|

Bracket

281826701

|

Heat

Sink

x

2

281810104

281816007.

257711802

Support

x

8

*

Bracket

x

4

Spacer

x

4

Bracket

Assembly

(Back)

Bracket

281816041

281916002

55060305F

|

T.R.

Rivet

x

12

257711806

|:

Spacer

x

4

55060365F

|

T.R.

Rivet

x

4

257711806

|

Spacer

YT0304003

|

Push

Type

Terminal

x

3

281926702

|

Heat

Sink

x

4

YT0204003

|

4P

Terminal

281926705

|

Heat

Sink

x

2

YTO208002

|

8P

Terminal

257700501

|

Clamper

x

2

Y¥J0400018

|

AC

Outlet

Jack

x

2

Y¥T0O201006

]

1P

Quad

Radial

Terminal

59110339H

|

Washer

x

2

281910101

|

Support

x

2

281815401

|

Knob

(Push)

x

8

281800450

|

Table

K

281815402

|

Knob

(Power)

x

8

273010950

|

Shield

K

(Front

End)

281815403

|

Knobx

3

273010902

|

Shield

(

”

)

281825701

|

Lid

273010903

|

Shield

(

”“

)x3

281825702

|

Lid

281916008

|

Bracket

x

2

257706302

|

Escutcheon

(Fly

Wheel)

281910901

{

Shield

257706303

|

Escutcheon

(Fly

Wheel)

281912002

|

Insulator

x

2

257727301

|

Fly

Wheel

281910902

|

Shield

28192650174

Indicator

281810701

|

Sheet

282210903

|

Shield

281810107

|

Support

x

4—

281810301

|

Pointer

281816009

|

Bracket

x

2

281810302

|

Pointer

281810906

|

Shield

281805301

|

Cover

(Pointer)

x

4

281810907

|

Shield

275905701

|

Leg

281926901

|

Protector

281930202

|

Dial

282126902

|

Protector

281810550

|

Chassis

K

282112001

|

Insulator

©

273010401.

|

Retainer

x

2

281912001

|

Insulator

x

2

281816003

|

Bracket

281915901

|

Brum

281816004

|

Bracket

71101569M

|

Spring

281816051

|

Bracket

K

281910701

|

Sheet

120225801

|

Hook

281805501

|

Collarx

5

273025901

|

Bushx

3

281827401

|

Reflector

138200503

|

Clamper

x

15

281827402

|

Reflector

72081602A

|

String

x

120

281827101

|

Holder.

257711803

|

Spacer

x

4

21

282111801

281900501

282100501

281927103

281905102

51570305B

51570306B

515703128

54050300R

51100306E

51040306A

51640412D

54040402A

53110403E

51570408B

515703068

-

51570306B

51042606S

51570306B

53110603A

54040602A

54020601E

53110303E

54050300R

51100306S

511003068

51570312B

51100304S

511003088

54050300R

53110303E

54050400R

51122608E

51100406S

54020401S

51570410B

54020401E

54040402N

51570306B

51100314E

51100306S

51102608E

Spacer

Clamper

x

2

Holder

(AM

Ant.)

Guide

(V.C

Stopper)

P.

H.

Tapt

Screw

x

8

P.H.

Tapt

Screw

x

7

P.H.

Tapt

Screw

x

5

T.

L.

Washer

x

2

B.

H.

M.

Screw

x

2

F.H.M.

Screw

x

2

Set

Screw

C

P

Spring

Washer

Hexagon

Nut

.

Tapt

Screw

x

2

.

Tapt

Screw

x

4

.

Tapt

Screw

x

6

.

M.

Screw

x

6

.

Tapt

Screw

x

3

.

Tapt

Screw

x

6

.

Tapt

Screw

x

2

.

Tapt

Screw

x

3

.

H.

Tapt

Screw

x

2

Hexagon

Nut

Spring

Washer

Flat

Washer

P

Hexagon

Nut

Hexagon

Nut

x

12

T.

L.

Washer

OR

x

4.

B.

H.

Tapt

Screw

x

6

H.

Tapt

Screw

x

3

H.

Tapt

Screw

x

2

H.

Tapt

Screw

x

2

H.

Tapt

Screw

x

2

H.

Tapt

Screw

x

4

H.

M.

Screw

x

2

H.M.

Screw

x

2

.

Washer

OR

x

2

x

exagon

Nut

x

2

.

L.

Washer

OR

.H.M.

Screw

x

4

.H:M.

Screw

x

10

B.

H.

M.

Screw

x

4

Flat

Washer

P

x

4

P.

H.

Tapt

Screw

x

4

Flat

Washer

P

x

4

Spring

Washer

x

4

P.

H.

Tapt

Screw

x

12

P.H.

Tapt

Screw

x

8

P.H.M.

Screw

x

8

MA

ATAHPH

YT

BBO

51060425E

54050400R

54040402E

53110403E

51100206E

54020201E

51570408B

53110403A

54020401A

54040502A

51060512A

53110501A

54020501A

62031650W

54050300R

51100306S

511003068

51100306S

511003068

51100306S

51570306B

62031650W

6203

1650W

51570306B

515703068

51570306B

515703068

51570306B

51650304D

53110403E

56382540G

51100310S

53110303E

54050300R

53112603E

54052600R

59030810P

54060300R

51060305E

51570306B

54040302N

a

Se

el

pig

oe

Ae

ola

re

oe

P.H.

M.

Screw

x

2

T.

L.

Washer

OR

x

2

Spring

Washer

x

2

Hexagon

Nut

x

2

B.H.M.

Screw

x

8

Flat

Washer

P

x

8

P.H.

Tapt

Screw

x

4

Hexagon

Nut

x

4

Flat

Washer

P

x

4

Spring

Washer

x

4

P.H.M.

Screw

x

4

Hexagon

Nut

x

4

Flat

Washer

P

x

8

Lug

x

5

T.

L.

Washer

OR

x

15

.

Screw

x

4

.

Screw

x

4

.

Screw

x

4

.

Screw

x

4

.

Screw

x

5

OD

0:

Od.

0

Stara

ate

.

Screw

x

4

.

Screw

x

5

.

Screw

x

4

.

Screw

x

4

.

Tapt

Screw

x

3

x5

.

Tapt

Screw

x

4

.

Tapt

Screw

x

4

.

Tapt

Screw

x

3

.

Tapt

Screw

x

8

Tapt

Screw

x

2

.

Tapt

Screw

x

4

.

Tapt

Screw

x

2

.

Tapt

Screw

x

4

.

Tapt

Screw

x

10

P.H.

Tapt

Screw

x

15

Set

Screw

H.

P.

x

2

Hexagon

Nut

x

2

Eyelet

£0

Oem

ols

ee

ope

wero

wit

B.

H.

M.

Screw

x

2

Hexagon

Nut

x

2

T.

L.

Washer

OR

x

2

Hexagon

Nut

T.

L.

Washer

OR

Fiber

Washer

T.

L.

Washer

x

5

P.H.

M.

Screw

x

3

P.H.

Tapt

Screw

x

2

Spring

Washer

x

4

Fi

DESIG.

PART

NO.

DESCRIPTION

R108-R

109

R110

R111-R113

C116-C117

C118

C119

C120-C121

C122-C125

C127

L101

L102

L103

L104

L105

H101

H102

YD2819002

(222819002)

RT

1056314

RT1010514

RT

1010414

RT

1022114

RT

1010214

RT

1047214

RT

1022314

RT1012214

RT1010114

RT

10223

14

RT1010114

CA4330001

CT1100001

CT

1100002

CT

1100001

CT1100001

DD1615001

DK1710201

DD1105001

DK1710201

DD1615001

DK1710201

DK1710301

DD1001001

DD1615001

DK1710301

DD

1620003

DD1210006

DD1615003

DK1710301

LA1202603

LA1202604

LA1202605

L01202603

L11001601

HF200191A

HF200191B

HT305351B

YP1000094

ELECTRICAL

PARTS

P.

C.

Board

P.

C.

Board

Assembly

RESISTORS

Carbon,

56KQ,

Carbon,

1MQ,

Carbon,

100KQ,

Carbon,

CAPACITORS

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+£10%,

1/4W

+10%,

1/4W

+10%,

1/4W

+10%,

1/4W

Variable,

FM4

AM3

Gang

Trimmer,

1.5pF~10pF

NPO

Trimmer,

1.5pF~10pF

NPO

Trimmer,

1.5p>F~10pF

NPO

Trimmer,

1.5pF~10pF

NPO

Trimmer,

1.5pF~10pF

NPO

Ceramic,

15pF,

Ceramic,

1000pF,

Ceramic,

5pF,

Ceramic,

1000pF

Ceramic,

15pF,

Ceramic,

1000pF,

Ceramic,

0.01uF,

Ceramic,

1.0pF,

Ceramic,

15pF,

Ceramic,

0.01uF,

Ceramic,

20pF,

Ceramic,

10pF,

Ceramic,

15pF,

Ceramic,

0.01uF,

Ceramic,

0.01uF,

TRANSFORMERS

Ant.

Coil

RF

Coil

RF

Coil

OSC

Coil

LFT

+10%,

SL

+20%,

YY

+0.5pF,

SL

+20%,

YY

+10%,

SL

+20%,

YY

+20%,

YY

+0.25pF,

SL

+10%,

SL

+20%,

+10%,

tipF,

+10%,

+20%,

SEMICONDUCTORS

Transistor,

2SK19Y

Transistor,

2SK19G

Transistor,

2SC535B

MISCELLANEOUS

REF.

MARANTZ

.

DESIG.

|

PART

NO.

DESCRIPTION

57271240W

YD2818002

(ZZ2818002)

RT

1033214

RT

1022414

RT

1039214

RT

1010414

RT

1022114

RT

1033214

RT

1015314

RT

1027214

RT

1018314

RT

1018414

RT

1010214

RT

1015214

RT

1018314

RT

1047314

RT

1010214

RT

1022114

RT

1015214

RT

1022214

RT

1047214

RT

1022414

RT

1022214

RT

1056214

RT

1010414

RT

1010214

RT1010114

RT

1022214

RT

1010114

RT

1082114

RT1056214

RT

1012314

RT

1082214

RT

1010114

RT

1056214

RT

1022214

RT

1010114

DF

1740301

DF1710301

DF1740301

DD1105001

DF1740301

DF1747201

DF

1722301

DF6545101

DF1740301

EA1060169

P.

C.

Board

Assembly

Carbon,

3.3KQ,

CAPACITORS

0.0047uF,+20%

0.022uF,

+20%

REF.

MARANTZ

;

DESIG.

PART

NO.

DESCRIPTION

C163

DF1740301

|

Mylar,

0O.04uF,

+20%

C164-C166

|

EA1060169

|

Elect.,

10uF,

16V

DK1710201

|

Ceramic,

0.001uF,

+20%

DF1747201

|

Mylar,

0.0047uF,+20%

DF1722201

|

Mylar,

0.0022uF+20%

DF1668301

}

Mylar,

O.068uF,

+10%

EA1060169

|

Elect.,

10uF,

16V

DF1740301

|

Mylar,

0.04uF,

+20%

EA1060169

|

Elect.,

10uF,

16V

DF1740301

|

Mylar,

O.04uF,

+20%

EA1060169

|

Elect.,

10uF,

16V

DF1740301

|

Mylar,

0.04uF,

+20%

EA1060169

|

Elect.,

10pF,

16V

DF1740301

|

Mylar,

0.04uF,

+20%

EA1060169

|

Elect.,

10uF,

16V

EA1060169

|

Elect,,

10uF,

16V

DD1620001

|

Ceramic,

20pF,

+10%

EA1070169

|

Elect.,

10uF,

16V

TRANSFORMERS

LA1001017

|

RF

Coil,

200uH

LO1001042

|

OSC

Coil,

120uH

L11028002

|

IFT

L11001048

|

IFT

L11028003

|

IFT

SEMICONDUCTORS

Transistor,

2SC941

(O)

Transistor,

2SC372

Transistor,

2SC372

Transistor,

2SC644

(T)

Diode,

1IN60

HT309411B

HT3037210

HT306441C

HD1000105

H157-H159

MISCELLANEOUS

Plug

J151-J162

YP1000094

P.

C.

Board

P.

C.

Board

Assembly

YD2819008

(ZZ2819008)

RESISTORS

RT1015114

|

Carbon,

1502,

+10%,

1/4W

RT1015214

|

Carbon,

1.5KQ,

+10%,

1/4W

RT1033214

|

Carbon,

3.3KQ,

+10%,

1/4W

R204-R205

|

RT1010214

|

Carbon,

1KQ,

+10%,

1/4W

R206

RT1082114

|

Carbon,

82092,

+10%,

1/4W

R207

RT1015114

|

Carbon,

15092,

+10%,

1/4W

R208

RT1015214

|

Carbon,

1.5KQ,

+10%,

1/4W

R209

RT1033214

|

Carbon,

3.3KQ,

+10%,

1/4W

R210-R211

|

RT1010214

|

Carbon,

1KQ,

+10%,

1/4W

R212

RT1010414

|

Carbon,

100KQ,

+10%,

1/4W

RT1015114

RT

1082114

150Q,

8202,

R213-R214

R215

+10%,

£10%,

Carbon,

24

R216

R217

R218

R219-R220

R221

R222

R223

R224

R225

R226

R227

R228-R229

R230

R231

R232

R233

R234

R236

R237

R238

R239

R240

R241

R242

R243

R244

R245

R246

R247

R248

R249-R252

C219-C225

REF.

MARANTZ

DESIG.

PART

NO.

RT1015114

RT1015214]°

RT

1033214

RT1010214

RT

1010414

RT1015114

RT

1022114

RT1082114

RT

1015114

Carbon,

.

Carbon,

RT

1082214

RT

1015314

RT

1010214

RT

1027114

RT1010414

RT

1082214

FT

1015314

RT1015114

RT1010214

RT1015114

Carbon,

RT

1010414

RT

1015114

RT

1047114

RT1010114

RT

1047214

RT

1012314

RT

1010214

RT

1022214

RT

1033314

RT

1056314

Carbon,

RT

1015314

RT1010114

RT

1022014

RT

1010314

RT

1018314

RT

1022314

RT

1027314

RT

1022314

RT

1012314

Carbon,

DK1710301

DK1710201

DK1710301

DK1810402

DK1710301

DK1810402

DK1840302

Ceramic,

DESCRIPTION

1502,

+10%,

1.5KQ,.

+£10%,

3.3KQ2,

+10%,

1KQ,

—

+10%,

100KQ,

+10%,

1502,

+10%,

2202,

+10%,

8202,

+10%,

1502,

+10%,

8.2KQ,

15KQ,

1KQ,

27022,

100KQ,

8.2KQ,

15KQ,

1500,

1KQ,

15022,

100KQ,

15022,

4702,

10022,

4.7KQ,

12KQ2,

1KQ,

2.2KQ,

33KQ,

56KQ,

15KQ,

10082,

2222,

10KQ,

18KQ,

22KQ2,

27KQ,

22KQ,

12KQ,

CAPACITORS

Ceramic,

0.01uF,

0.01pF,

0.01uF,

O.01uF,

0.01uF,

0.001uF

0.01uF,

0.1uF,

0.04uF,

’

+10%,

‘+10%,

+10%,

+20%

+80%,

+20%

+80%,

1/4w

1/4W

1/4w

1/4W

.

1/4W

~—20%

—20%

INTRODUCTION

This

service

manual

was

prepared

for

use

by

Authorized

Warranty

Stations

and

contains

service

information

for

Marantz

Model

2245

Stereophonic

Receiver.

Servicing

information

and

voltage

data

included

in

this

manual

are

intended

for

use

by

the

knowledgeable

and

experienced

technician

only.

All

instruction

should

be

read

carefully.

No

attempt

should

be

made

to

proceed

without

a

good

understanding

of

the

operation

in

the

receiver.

The

parts

list

furnish

information

by

which

replacement

part

may

be

ordered

from

the

Marantz

Company.

A

simple

description

is

included

for

parts

which

can

be

usually

be

obtained

through

local

suppliers.

1.

Service

Notes

As

can

be

seen

from

the

circuit

diagram

the

chassis

of

Model

2245

consists

of

the

following

units.

Each

unit

mounted

on

a

printed

circuit

board

is

described

within

the

square

enclosed

bya

bold

dotted

line

on

the

circuit

diagram.

é

1.

FMFrontEnd

.......

02.2

ee

eee

ee

te

ees

mounted

on

P.C.

Board,

P100

2.

FM

IF

Amplifier

2...

0.

ce

ee

mounted

on

P.C.

Board,

P200

3.-FM

Detector

.......

0.000

ee

ewe

ee

et

te

es

mounted

on

P.C.

Board,

P500-

4.

MPX

Stereo

Decoding

Amplifier

........-...+-:

~.

,

.

mounted

on

P.C.

Board,

P300

5.

Muting

Control

Amplifier

2...

0.6.6.

ee

es

mounted

on

P.C.

Board,

P550

6.

AM

Tuner

Unit

.........

00

eee

ee

te

es

mounted

on

P.C.

Board,

P150

7.

Phono

Amplifier...

0.0...

ee

eee

mounted

on

P.C.

Board,

P700

8.

Tone

Amplifier...

0...

ee

es

mounted

on

P.C.

Board,

P400

9.

PowerAmplifier

2.2...

0...

eee

ee

es

mounted

on

P.C.

Board,

P750

10.

Regulated

Power

Supply

and

Protection

Relay

Circuit...

.

mounted

on

P.C.

Board,

P800

11.

Loudness,

High

and

Low

Filter,

and

Muting

Switch

Unit

. . .

mounted

on

P.C.

Board,

P600

2:

AM

Tuner

All

components

except

Tuning

capacitor

and

ferrite

bar

antenna

are

mounted

on

a

printed

circuit

board

P150.

The

AM

signals

induced

in

a

ferrite

bar

antenna

are

applied

to

the

base

of

RF

amplifier

transistor

H151

through

a

capacitor

of

C151

and

amplified

to

the

level

required

for

overcoming

the

conversion

noises,

thus

giving

good

S/N

performance.

The

tuned

circuits

inserted

in

both

out

and

input

circuit

of

the

RF

amplifier

assure

very

high

image

and

spurious

rejection

performance.

Thus

amplified

and

selected

AM

signals

are

then

applied

to

the

base

of

converter

transistor

H152

through

a

coupling

capacitor

C156.

While

the

local

oscillator

voltage

is

injected

to

the

emitter

of

H152

through

a

capacitor

C157.

Both

AM

signals

and

oscillating

voltage

are

mixed

at

the

base-emitter

junction

and

converted

into

455KHz

intermediate

frequency.

The

resulting

IF

signal

is

applied

to

the

first

IF

transformer

L153

consisting

of

one

ceramic

filter

and

two

tuned

circuits.

The

output

of

L153

is

led

to

the

transistor

H153

which

in

turn

apply

its

output

to

the

transistor

of

H154.

The

fully

amplified

IF

output

is

then

applied

to

the

diode

H157

to

detect

audible

signal

through

the

detector

transformer

L154.

The

detected

audio

signal

is

filtered

and

amplified

and

the

final

audio

output

is

obtained

from

the

collector

of

H155

and

applied:

one

to

the

tape

out

jacks

through

monitor

switch

on

the

front

panel

and

the

other

to

the

function

rotary

switch.

P

The

DC

component

of

the

detected

IF

signal

is

used

as

a

AGC

voltage

to

control

emitter

current

of

H153

which

in

turn

control

the

bias

current

of

the

RF

amplifier

through

the

resistor

R179

and

R151.

A

part

of

IF

signal

output

is

also

applied

to

the

diode

H158

through

a

capacitor

C167

and

rectified

to

obtain

DC

current

for

energizing

the

AM

signal

strength

meter

Mo01.

Suggestions

for

AM

Tuner

Trouble

Shooting

Check

for

broken

AM

bar

antenna,

to

tune

station

by

rotating

fly-wheel

tuning

knob

slowly

and

observe

the

AM

signal

strength

meter

whether

it

deflects

or

not.

If

the

signal

strength

meter

gives

a

deflection

at

several

frequencies

received,

no

failure

may

exist

in

the

stages

at

least

preceding

final

IF

transformer

L154.

a.

oscilloscope

to

the

terminal

J162

or

J157

and

check

for

audio

signals

with

the

tuning

meter

deflected.

If

the

signal

strength

meter

does

not

deflect,

check

the

local

oscillator

circuit.

Normal

oscillating

voltage

at

the

hot

end

of

the

oscillator

tuning

capacitor

is

about

2

or

3

volts,

varying

with

tuning

capacitor

position.

When

measuring

oscillating

voltage

use

a

RF

VTVM,

no

circuit

tester

gives

correct

indication.

If

the

local

oscillator

voltage

is

normal,

check

all

voltage

distribution

in

the

AM

circuits

by

using

a

DC

VTVM

and

compare

the

measured

values

with

those

given

in

the

schematic

diagram.

3.

FM

Tuner

The

FM

Tuner

section

of

Model

2245

is

divided

into

five

functional

blocks:

FM

Front

End,

IF

Amplifier,

Detector,

Muting

Control

and

MPX

Stereo

Decoding

Circuit.

-

FM

signals

induced

by

a

FM

antenna

are

led

to

FM

antenna

coil

L101

through

an

attenuator

switch

and

a

Balun

coil.

These

signals

are

then

applied

to

the

FET

RF

amplifier

which

in

turn

applies

its

output

to

the

Mixer

H102

through

the

double

tuned

high

selective

circuits.

The

FET

Mixer

convert

its

input

signal

into

10.7MHz

intermediate

frequency

and

amplifies

it

at

the

same

time.

The

H103

is

a

local

oscillator

and

its

output

is

injected

into

the

source

of

the

FET

Mixer,

the

injection

voltage

is

about

7OOmV.

The

10,7MHz

front

end

output

is

led

to

the

amplifier

unit

through

a

coaxial

cable.

The

IF

amplifier

unit

consists

of

five

stages

of

1F

amplifier

and

one

stage

of

AGC

amplifier.

Six

pieces

of

ceramic

filters

are

also

used

to

obtain

high

selectivity

four

stages

of

symmetrical

diode

limiters

are

also

employed

for

the

best

limitting

characteristics,

improved

capture

ratio

and

good

AM

suppression.

A

part

of

FM

Front

End

output

is

applied

to

the

AGC

amplifier

H206

and

rectified

its

output

is

fed

back

to

the

gate

of

FET

RF

amplifier

to

decrease

the

gain

with

increased

signal

strength.

The

IF

signal

sufficiently

amplified

through

every

stage

of

IF

amplifier

is

finally

applied

to

the

IC

limiter

on

the

Detector

Unit.

The

detected

audio

output

is

led

to

the

buffer

amplifier

H502

and

its

buffered

output

is

led

to;

(a)

noise

amplifier

H551

through

resistor

R551

and

capacitor

C551,

(b)

Quad

Radial

Jacks

on

the

rear

panel

through

resistor

R564,

(c)

MPX

stereo

decoding

circuit

through

R563.

_

The

DC

current

caused

at

the

third

windings

of

the

discriminator

transformer

is

directly

applied

to

the

FM

center

tuning

meter.

Marantz 2245 User manual

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